The present invention relates to a telescopically extensible drill.
Extensible drills are used, for instance, for rock drilling purposes, e.g. for drifting tunnels. The drills are used to drill holes intended for receiving explosive charges for instance. When applying known techniques, the drilling machine or drilling equipment used is constructed for advancement along a so-called drill guide-bar or feed bar. Such rock drills will preferably operate in the manner of hammer drills, i.e. drills which subject the drill to axially-directed impacts while the drill rotates. With known techniques, the length of the drill is extended during a drilling operation, by joining the drill to one or more drill rods, so that the requisite depth of the drill hole can be achieved. This is effected, for instance, by placing a rack of drill rods adjacent the drill guide-bar. The work of splicing or otherwise joining the drill-rod(s) to the drill is normally automated or effected with the aid of mechanical devices. Unfortunately, this requires the provision of relatively complicated peripheral equipment. The drill-rod magazine with associated equipment is also bulky and space consuming.